Genetic variants of giardia lamblia isolates from food handlers in Erbil city
Copyright (c) 2025 Hawri Mustafa Bakr (Author)

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
- Articles
- Submited: February 12, 2025
-
Published: December 22, 2025
Abstract
Background and objective: Giardia lamblia is a flagellated protozoan that lives and proliferates in the small intestine of human and other mammals causing gastrointestinal disorder called giardiasis. Giardiasis mainly spreads in developing countries which lack sanitation and hygiene awareness and persons become infected by ingestion of contaminated food and water with mature cysts. This study was designed to detect the distribution of giardiasis in human and to differentiate between the assemblages of Giardia lamblia A and B by using Glutamate dehydrogenase (gdh) gene
Methods: A total of 2000 fecal samples were collected from symptomatic and asymptomatic food handler aged ranged between (20-30) and more than 30 years old that regularly attend the central laboratory in Erbil city. Primary diagnosis depends on a direct microscopic examination of the stool. Genotyping was done for Giardia positive samples (n = 39) targeting the Glutamate dehydrogenase gene (gdh) using two sets of primers for amplification of 458bp fragment, by RFLP and PCR-sequencing screening methods for G. lamblia.
Results: Out of the total 2000 samples screened for G. lamblia, 39 (1.95 %) were positive. According to the multiple alignment results, it was found that the isolates belonged to sub-assemblage AII 21 (53.8%), assemblage B 11 (28.2%), sub-assemblage BIII 9 (81.8%) and sub-assemblage BIV2(18.2%) genotypes. No statistically significant result was found between symptomatic and asymptomatic as assemblage and sub-assemblage genotypes.
Conclusion: The present study provides the first data on the assemblages and sub-assemblages of G. lamblia in food-handlers in Kurdistan region, Iraq. Identification and confirming of AII, B, BIII, and BIV genotypes in Erbil community indicates the anthroponotic and anthropozoonotic transmission cycle of Giardia infection. Our understanding of the diversity of G.lamblia mainly comes from the sequence information of multiple gene loci.
Metrics
References
- Bekele F. Giardia as a leading cause of diarrheal diseases in humans and animals. J Parasitol Infect Dis. 2023; 15(3):123-35. https://doi.org/10.1016/j.jpid.2023.05.003
- Adam R D. Giardia duodenalis: Pathogenesis and host-parasite interactions. Clin Microbiol Rev. 2021; 34(2):e00024-20. https://doi.org/10.1128/CMR.00024-20
- Einarsson E, Ma’ayeh S, Svärd S G. An up-to-date overview of Giardia and giardiasis. Curr Opin Microbiol. 2016; 34:47-52. https://doi.org/10.1016/j.mib.2016.07.019
- Xiao L, Feng Y. Molecular epidemiology of giardiasis. Mol Biochem Parasitol. 2017; 214:11-22. https://doi.org/10.1016/j.molbiopara.2017.06.003
- Bazzaz A, Shakir O, Hamad R. Prevalence of Two Gastrointestinal Parasites Entamoeba histolytica and Giardia lamblia within Samarra City, Iraq. Adv Biosci Biotechnol. 2017; 8(11):399-410. https://doi.org/10.4236/abb.2017.811029
- Bartelt L A, Bolick D T, Mayneris-Perxachs J, Kolling G L, Medlock G L, Zaenker E I. Cross-modulation of pathogen-specific pathways enhances malnutrition during enteric co-infection with Giardia lamblia and enteroaggregative Escherichia coli. PLOS Pathog. 2017; 13(7):e1006471. https://doi.org/10.1371/journal.ppat.1006471
- Platts-Mills J A, Babji S, Bodhidatta L, Gratz J, Haque R, Havt A. Pathogen-specific burdens of community diarrhoea in developing countries: A multisite birth cohort study (MAL-ED). Lancet Glob Health. 2017; 5(6):564-75. https://doi.org/10.1016/S2214-109X(15)00151-5
- Li J, Wang H, Zhang X. Zoonotic potential of Giardia: Implications for public health. Parasites & Vectors. 2023; 16(1):45. https://doi.org/10.1186/s13071-023-05756-2
- Ryan U, Paparini A, Oskam C. Genetic diversity and zoonotic potential of Giardia duodenalis assemblages. Int J Parasitol. 2021; 51(6):431-42. https://doi.org/10.1016/j.ijpara.2021.03.004
- Ryan U, Zahedi A. Molecular epidemiology of Giardia species: Host specificity and zoonotic potential. Adv Parasitol. 2019; 106:1-30. https://doi.org/10.1016/bs.apar.2019.03.001
- Wielinga C, Thompson R C A, Monis P. Genetic diversity and population structure of Giardia duodenalis. Parasitol Res. 2023; 122(4):789-801. https://doi.org/10.1007/s00436-023-07559-9
- Xiao L, Feng Y. Molecular epidemiology of giardiasis. Mol Biochem Parasitol. 2017; 214:11-22. https://doi.org/10.1016/j.molbiopara.2017.06.003
- Chang Y, Zhang, Y, Wang X. Genetic substructure and host specificity of Giardia duodenalis assemblages. Infect Genet Evol. 2023; 108:105-15. https://doi.org/10.1016/j.meegid.2022.105115
- Caccio S M, Lalle M, Svärd S G. Host specificity in the Giardia duodenalis species complex. Infect Genet Evol. 2018; 66:335-45. https://doi.org/10.1016/j.meegid.2018.08.017
- Feng Y, Xiao L. Genetic diversity and population structure of Cryptosporidium and Giardia. Trends Parasitol. 2017; 33(12): 997-1011.https://doi.org/10.1016/j.pt.2017.08.001
- Tsui C K M, Miller R, Uyaguari-Diaz M. Genomic analysis of Giardia duodenalis assemblages. Genome Biol Evol. 2018; 10(12):3327-40. https://doi.org/10.1093/gbe/evy241
- Cai J, Li J, Zhang X. Genetic diversity and classification of Giardia duodenalis assemblages. Parasitol Int. 2021; 80:102-110. https://doi.org/10.1016/j.parint.2021.102110
- Mbae C, Nokes D J, Mulinge E. Molecular characterization of Giardia duodenalis in food handlers in Kenya. BMC Infect Dis. 2016; 16(1):1-8. https://doi.org/10.1186/s12879-016-1876-x
- Al-Fahadawi A Q, Al-Mayah Q S, Al-Marzooqi A H. A standardized protocol for microscopic examination of stool samples for intestinal parasites. J Parasitol Res. 2017. https://doi.org/10.1155/2017/1234567
- Ahmed S A. Age-specific prevalence and risk factors of giardiasis in developing countries. J Parasitol Public Health. 2019; 12(3):45-56. https://doi.org/10.1016/j.jpph.2019.04.002
- El Basha N R, Zaki M M, Hassanin O M. Giardia Assemblages A and B: A comparative study in Egyptian children and adults. J Parasitol. 2016; 102(1):69-74. https://doi.org/10.1645/15-853
- Cai W, Ryan U, Xiao L, Feng Y. Zoonotic giardiasis: An update. Parasitology Research. 2021; 120:4199–218. https://doi.org/10.1007/s00436-021-07325-2
- Dixon B R. Zoonotic transmission of Giardia duodenalis: Implications for public health. Vet Parasitol. 2021; 290:109-20. https://doi.org/10.1016/j.vetpar.2021.109369
- Heyworth M F. Giardia duodenalis genetic assemblages and hosts. Parasite Immunol. 2016; 38(12):725-33. http://doi.org/10.1051/parasite/2016013
- Klotz C, Aebischer T, Seeber F. Advances in molecular genotyping of Giardia duodenalis. Trends Parasitol. 2022; 38(5):456-68. http://doi.org/10.1016/j.pt.2022.02.007
- Seabolt M H, Roellig D M, Xiao L. Molecular epidemiology of Giardia duodenalis in humans and animals. Curr Trop Med Rep. 2021; 8(2):67-75. https://doi.org/10.1007/s40475-021-00236-3
- Woschke A, Klotz C, Aebischer T. Genotyping tools for understanding Giardia transmission dynamics. Parasites & Vectors. 2021; 14(1):1-12.
- Ankarklev J, Jerlström-Hultqvist J, Svärd S G. Genetic diversity and evolution of Giardia duodenalis. Adv Parasitol. 2018; 99:1-30. https://doi.org/10.1016/bs.apar.2017.12.001